INCOME TAXES - Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Net changes in the liability for unrecognized tax benefits
Balance at the beginning of the period	$ 12,619	$ 7,306
Additions (reductions) for tax positions taken in prior years	3,641
Recognition of benefits from expiration of statutes	(359)	(1,068)
Other		(3,125)
Additions for tax positions related to the current year	986	472
Additions for tax positions related to current year acquisitions	45	2,784
Balance at the end of the period	16,932	12,619	$ 7,306
Unrecognized tax benefits from permanent tax adjustments that, if recognized, would affect the effective rate	7,500	4,500
Unrecognized tax benefits related to settlements with taxing authorities	4,400
Interest and penalties accrued	1,600	1,200
Total liability for uncertain tax issues	15,500	10,900
Cash amounts paid for income taxes, net of refunds received	$ 14,200	$ 15,200	$ 27,300